Real-world treatment switching and sequencing to next line of therapy of zanubrutinib, acalabrutinib, and ibrutinib in chronic lymphocytic leukemia or small lymphocytic lymphoma

Background Assessing Bruton tyrosine kinase inhibitors (BTKis) for treating chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is crucial to understand associated real-world outcomes in diverse populations. This study evaluated real-world treatment patterns, switching, and sequencing to next line of therapy in patients initiating BTKis as first-line (1 L) or second-line (2 L) CLL/SLL treatment.Research design and methods The IntegraConnect PrecisionQ database was used to identify CLL/SLL patients initiating 1 L or 2 L zanubrutinib, acalabrutinib, or ibrutinib (1/1/2020-2/28/2023). Switching was measured as patients initiating another treatment within the same line or advancing to following line of therapy within 90 days. Sequencing to next line of therapy was calculated from time to the next treatment Kaplan-Meier curve.Results 2816 and 1253 patients initiated 1 L or 2 L BTKi (zanubrutinib, 157/107; acalabrutinib, 1238/672; ibrutinib, 1421/474), respectively. The 90-day switching rate was significantly lower for zanubrutinib vs. acalabrutinib and ibrutinib (1 L: p < 0.0001; 2 L: p < 0.0001). Estimated proportion of patients receiving next line of therapy at 180 days was lower for zanubrutinib vs acalabrutinib and ibrutinib (1 L p = 0.2958; 2 L p < 0.0001).Conclusions Zanubrutinib was associated with lower 90-day switching rates and estimated proportion of patients receiving next line of therapy at 180 days vs. acalabrutinib and ibrutinib in 1 L and 2 L.